If anyone ever asks you to explain what the saying "less is more" is all about, Apple Computer's new iBook makes a great illustration.

The new model has only half the mass of the original iBook design -- 137.6 cubic inches for the new version, 281 for the old one, according to calculations Mac nerds began posting online within hours of the new product's announcement May 1. And the comparison to Windows laptops is only slightly less dramatic. Dell's Inspiron 2500, for example, fills 235 cubic inches, while the IBM ThinkPad iSeries 1200 comes in at 169.

Yet the iBook offers all the capabilities of its forebears -- and more than most of its competitors.

While the curvaceous original iBook inspired comparisons to things like Barbie accessories and toilet seats, the new one, with a strictly rectangular design measuring 11.2 inches wide, 9.1 inches deep and 1.35 inches thick, truly deserves to be called a notebook -- an extra-thick one, anyway.

The trimmer shape also means less burden on your shoulders when you're carrying the device. Its weight is 4.9 pounds -- more than sleek-but-much- pricier models like the Sony Vaio 505, but 2 pounds less than its predecessor, 1.85 less than the Inspiron 2500 and 1.1 less than the ThinkPad.

In terms of color, Apple has -- for now, at least -- taken a more- conservative turn, but it continues to "think different." While old iBook shades like key lime are gone, Apple has not adopted the gray or black that are pervasive among its notebook competitors. Instead, the new iBook is available only in shiny white. (There are hints, though, that more colors may be coming before long.)

Heft and looks aside, the new iBook also makes progress on the price front.

The base model, with a 500-MHz PowerPC G3 processor, 64 MB of RAM, a 10-GB hard drive, a 12.1-inch screen and a built-in CD-ROM drive, goes for $1,299 -- $200 less than the least-expensive previous iBook. For students, the price is $1,249, and for educational institutions it's $1,199.

A version that's otherwise identical but has a DVD drive and 128 MB of RAM sells to consumers for $1,499, while one with the same memory and a read-write CD drive will be available soon at $1,599.

From Apple's online store or from dealers who order through it, you'll also be able to order a version with a combination CD-RW/DVD drive ($1,799) or choose a 20-GB hard drive, more memory (up to 640 MB) or other build-to-order options.

But when you take a closer look, Apple's offering begins to look like a much better bargain, because it has capabilities and features for which you would have to pay competitors extra.

-- ETHERNET. While nearly all PC notebooks these days have 56-Kbps modems built in, Apple complements its modem with an Ethernet jack. That makes it a breeze not only to connect to office or campus networks, but also to hook up to a cable or DSL modem at home or simply to share files with a desktop computer.

-- FIREWIRE. Alongside the usual USB ports, the iBook has a FireWire connector built in. That technology (a.k.a. IEEE 1394 or i.Link) is the standard for connecting digital video cameras to computers. (The machine comes with a copy of iMovie2, Apple's easy-to-use video editing software). It's also a fast and easy way to hook up external hard drives, scanners and other peripherals -- without the slowdown the current version of USB imposes.

-- VIDEO OUT. If you'd like to use a larger screen with the iBook when you're at your desk, it also has a port and cable adapter for connecting to standard VGA monitors. I tried it with a 19-inch display, and it worked fine, with a few restrictions. Resolution is limited to a maximum of 1,024 by 768 pixels, and it works only in "mirroring" mode (same content on both built-in and external displays).

For those who want to hook up to a TV or video monitor -- for a presentation, for example, or to watch a DVD movie -- the iBook also has a separate composite video port. That requires a different cable adapter, for which Apple charges $20.

-- WIRELESS READY. Like its predecessor and all other recent Macs, the new iBook has a built-in antenna and a special internal slot for adding an Apple AirPort wireless local-area networking card. You can add the same capability to PC notebooks, but at $99, Apple's card is a bit cheaper than most of the PC alternatives.

-- BATTERY. Even if you have no use for any of these features, you're bound to appreciate the iBook's battery life. Apple rates it at five hours, compared,

for example, with the 2.6 hours IBM claims for its iSeries 1200 or the meager 1 to 1.5 hours provided by the standard Inspiron 2500 battery.

Take all such claims with a grain or two of salt, but Apple doesn't seem to be exaggerating more than the rest. When I first took the new iBook out of the box, it ran for about four hours of steady use -- including installing Microsoft Office 2001 and playing music CDs in the background -- before I ever plugged it in. And after I recharged the battery, I got about 4 hours and 25 minutes of use from it.

-- SCREEN. At 12.1 inches (measured diagonally), the iBook's screen is the same size as those in competing models. But its default resolution is 1,024 by 768 pixels, compared with the 800 by 600 pixels standard in most 12.1-inch screens, including those in earlier-generation iBooks -- as well as the Dell and IBM models mentioned above.

For most computer specs, bigger numbers are better, and most of us assume the same about resolution. In reality, increasing resolution on a screen of fixed physical size is a mixed blessing: You get more information on screen, but that information is necessarily smaller.

While that's often a good thing when you're looking at graphics or headlines, it can make standard-size text and numbers difficult to read, at least for those of us whose eyes aren't what they used to be.

For me, though, this turned out to be less of an issue than I had feared when I first heard the specs -- partly because the Apple screen is exceptionally bright and crisp, and partly, I think, because one tends to sit closer to a notebook computer than to a desktop. I found 9-point type was a bit problematic, but 10- and 12-point text looked fine.

(You can reduce the iBook's resolution to 800 by 600 or even 640 by 480 pixels, but I don't recommend that solution -- image quality isn't nearly as good as at the default settings.)

On the whole, if reading small type is a challenge for you, it's a good idea to try out the screen for yourself -- with the kinds of documents you actually work with -- before making a commitment to the new iBook. For most people, though, I suspect the high resolution will be a plus, not a problem.

-- SOME CAVEATS.Unfortunately, there are always some trade-offs associated with low prices, small size and long battery life, and the iBook is no exception. While its 500-MHz processor is pretty fast -- faster than an Intel or AMD chip at the same clock speed -- it's not as zippy as the 1-GHz chips found in new high-end PC notebooks. And because it's a G3 rather than a G4, it won't fly through things like Adobe Photoshop filters as fast as Apple's latest PowerBooks and desktop Power Macs.

While few users are likely to care about -- or even notice -- the absence of an infrared port, I for one was sorry Apple chose to omit an analog audio- in port. If you want to digitize old records, for example, you'll need to add a third-party USB adapter.

The machine does have a microphone built into the frame of its screen, and there's a headphone jack on the side. That's a good thing, because the built- in stereo speakers are pretty awful. They're no worse, I guess, than those in most PC portables, but I'd hoped for better from Apple.

Like its predecessor, the new iBook also lacks a PC Card (a.k.a. PCMCIA) slot. Considering all the features built into the iBook, that won't be a problem for most users, but if you want to connect to SCSI peripherals or add a Ricochet wide-area wireless networking card, for example, the iBook is not for you, unless you're willing to settle for external adapters.

I also have one quarrel with the iBook's design: All the ports and connectors are on the sides (the AC plug on the right, the others on the left).

The system had to be designed that way, Apple product managers told me, because the bottom of the screen drops down when it's opened into the area where cables would normally be connected.

That begs the question of why the hinge was designed that way. It's not a big point, but I would have preferred a screen that would let me keep my power line, modem cable and so on out of sight.

-- BOTTOM LINE. These are relatively minor issues, though -- especially when you look at the trade-offs involved with competing laptops in the iBook's price range. On the whole, Apple has delivered a remarkably capable machine in an attractive and compact package and at a relatively affordable price. It's bound to be a hit among Mac users, and I think it's probably good enough to win over a few more Windows users to the Apple camp.

At the very least, it gives PC-notebook-makers something new to try to match.